Arnd, On Thu, May 15, 2014 at 1:17 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Wednesday 14 May 2014 17:33:02 Andrew Bresticker wrote: >> + >> +int tegra_xhci_register_mbox_notifier(struct notifier_block *nb) >> +{ >> + int ret; >> + >> + mutex_lock(&tegra_xhci_mbox_lock); >> + ret = raw_notifier_chain_register(&tegra_xhci_mbox_notifiers, nb); >> + mutex_unlock(&tegra_xhci_mbox_lock); >> + >> + return ret; >> +} >> +EXPORT_SYMBOL(tegra_xhci_register_mbox_notifier); >> + >> +void tegra_xhci_unregister_mbox_notifier(struct notifier_block *nb) >> +{ >> + mutex_lock(&tegra_xhci_mbox_lock); >> + raw_notifier_chain_unregister(&tegra_xhci_mbox_notifiers, nb); >> + mutex_unlock(&tegra_xhci_mbox_lock); >> +} >> +EXPORT_SYMBOL(tegra_xhci_unregister_mbox_notifier); > > What driver would use these? It's used by just this driver (the host) and the PHY driver (next patch in series). > My feeling is that if you have a mailbox that is used by multiple > drivers, you should use a proper mailbox driver to operate them, > and have the drivers register with that API instead of a custom one. Ok, will do. >> + /* Create child xhci-plat device */ >> + memset(xhci_resources, 0, sizeof(xhci_resources)); >> + res = platform_get_resource(to_platform_device(dev), IORESOURCE_IRQ, 0); >> + if (!res) { >> + dev_err(dev, "Missing XHCI IRQ\n"); >> + ret = -ENODEV; >> + goto out; >> + } >> + xhci_resources[0].start = res->start; >> + xhci_resources[0].end = res->end; >> + xhci_resources[0].flags = res->flags; >> + xhci_resources[0].name = res->name; >> + res = platform_get_resource(to_platform_device(dev), IORESOURCE_MEM, 0); >> + if (!res) { >> + dev_err(dev, "Missing XHCI registers\n"); >> + ret = -ENODEV; >> + goto out; >> + } >> + xhci_resources[1].start = res->start; >> + xhci_resources[1].end = res->end; >> + xhci_resources[1].flags = res->flags; >> + xhci_resources[1].name = res->name; >> + >> + xhci = platform_device_alloc("xhci-hcd", PLATFORM_DEVID_AUTO); >> + if (!xhci) { >> + dev_err(dev, "Failed to allocate XHCI host\n"); >> + ret = -ENOMEM; >> + goto out; >> + } > > This does not feel appropriate at all: Rather than creating a child device, > you should have a specific driver that hooks into functions exported > by the xhci core. See Documentation/driver-model/design-patterns.txt This is how DWC3, currently the only in-tree non-PCI XHCI host driver, is structured - see drivers/usb/dwc3/host.c. The recently proposed Armada XHCI driver [1] just adds clock support and a hook in xhci-plat's probe() to do the platform-specific initialization. Tegra's XHCI driver initialization is quite a bit more complicated, mainly due to the need for external firmware and specific ordering (e.g. firmware messages should only be enabled after the HCD is created). I could do away with the xhci-plat sub-device and just create a Tegra hc_driver, but it seems silly to have three XHCI platform drivers structured in three different ways. USB folks, do you have an opinion on how this should be done? [1] https://lkml.org/lkml/2014/5/15/208 Thanks, Andrew -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html